On or over the roads is OB... This is to keep you from throwing into the fairway of another group... If it is a casual round I would suggest playing this way as practice makes perfect... but at that point it is up to you. Most non PDGA tourneys will use the PDGA rules with some exceptions being made for weather and course conditions... an example would be a pool of water being casual in the winter time that would never exist in the summer time.